Step 1: Check WiFi Settings
2. Turn on Wifi, but don’t connect to a wireless network
3. Go to system preferences and turn on internet sharing. Your configuration should look like the photo above.
Step 2: Create WiFi Network
Step 3: WiFi Confirmation
2. Find an Android tablet running v4.1 or later. Connect to the wireless network you just created.
3. Download the Chromecast App from the Google Play store on your tablet.
4. Follow all the onscreen instructions. If successful, you should see the Ready to Cast text in the upper left corner of your TV screen.
5. To test your connection, go to the YouTube app on your tablet. Pick any video and play it. In the upper right corner, you should see a TV/beam icon. Once you press it, Chromecast connects and begins to play your video. At this point you can go do other things on your tablet while the video is playing.